Query Revaluation Method For Legal Information Retrieval

It is of great importance to give prior cases for the Common Law system2. A prior case (also called a precedent) is an older court case related to the current case, which discusses similar issue(s) and which can be used as a reference in the current case [1]. Therefore, legal practitioners need to find and study prior cases to study how to explain current issues in older cases. Artificial Intelligence for Legal Assistance (AILA) is a series of shared tasks aimed at developing datasets and methods for solving a variety of legal informatics problems [2]. AILA20203, which aims to develop an automatic system and focused on precedent and statute retrievals for a given legal scenario [5]. This year AILA will consist of two different tasks. Task 1 is the same as AILA 2019 and we will focus on task 1a in this paper. Generally, legal information retrieval is regarded as a rank task. Last year, we proposed an improvement of BM25 and achieved excellent results [3]. As early as 2004, the multiple weighted fields base on BM25 were proposed by Robertson [4]. So we will continue to improve the method of last year in 2020.